The present invention relates to medical treatment devices. In particular, the present invention relates to an introducer sheath and hub for use with medical treatment devices that emit energy in connection with the performance of medical procedures. The present invention also relates to an introducer sheath and hub that may be used with other devices, such as those used in medical procedures.
One such medical device using energy is for vein ablation. Vein ablation is a procedure that may be used to treat varicose veins. Varicose veins exist because valves in the blood veins fail, allowing blood to stagnate. This stagnation causes pain and noticeable purple or red traces of the vein visible from the outside of the skin. During a normal vein ablation procedure for varicose veins, a practitioner first identifies a vein or veins for the procedure. The veins are then mapped as a guide for the practitioner in order for him to perform the procedure. Once the veins are mapped, the practitioner prepares the vein for ablation by introducing a sheath into a far end of the vein, in preparation for introduction of a treatment device, such as a laser or radio frequency device.
The treatment device is introduced into the vein at the distal end and extended in the vein to a junction with a healthy branch of a larger vein to ensure that the entire damaged vein is treated. In a laser treatment procedure, a fiber-optic member is covered by a sheath for introduction and for the treatment procedure. As fiber-optic members are usually very slender fibers of glass, it is not desirable to introduce the fiber-optic member without a covering because the fiber can break off in the patient, or can puncture the vein walls, damaging surrounding tissues.
Thus, the fiber-optic member is introduced in a sheath or catheter and advanced to the beginning of the treatment area. The practitioner can determine the location of the tip of the fiber-optic member in the patient by ultrasound imaging, transillumination of the anatomy using an aiming or targeting beam, by feel, and/or by estimating the location based on a calculated position inside of the vein targeted for treatment. Once the fiber-optic member reaches the beginning of the treatment area, the practitioner exposes a terminal portion of the fiber-optic member by extending the fiber-optic member out of the end of the sheath, exposing about 2 cm of fiber. To expose the end of the fiber, a practitioner looks at marks positioned on the fiber near a hub, indicating to the practitioner a position where the end of the fiber is inside of the sheath, and where the fiber is extended out of the sheath about 2 cm. The laser is then activated and transmits energy through the fiber, thereby heating the tissue and fluid around the end of the treatment fiber, effectively destroying the vein and preventing further filling of the vein with stagnant blood. The ablation procedure removes the appearance of the varicose vein, alleviates the pain caused by the varicose vein, and prevents further complications.
Additionally, in a traditional ablation procedure, a practitioner needs to monitor the energy expended by the laser to ensure sufficient treatment of the target veins. One way to see where the end of the treatment catheter is located inside of the patient is by seeing light through the patient's skin before or during the laser treatment of the target area. Light in the visible spectrum, which may be a targeting light, may be used. Thus, practitioners often dim the lights, allowing better viewing of the monitors and of the treatment location in the patient. However, the low-light conditions make seeing the marks on the fiber difficult, creating the possibility of errors because of misreading the marks. Thus, in placing a fiber for treatment into a patient in a traditional ablation procedure, a practitioner needs to identify markings on the fiber in very low light, simultaneously monitoring treatment, location of treatment, and patient comfort.
Some previous efforts to solve some of the problems associated with vein ablation procedures include, for example, a device and method disclosed in U.S. Patent Publication No. US 2006/0142747. In the disclosed device, a split straw is used to maintain a fiber inside of a sheath during insertion and prior to using the laser. The split straw includes a portion over the fiber, preventing the fiber from advancing in the sheath past a point where the terminal end of the fiber would be exposed outside of the sheath. The split straw also includes a second handle portion to aid in removing the split straw from the fiber, allowing a terminal end of the fiber to be advanced outside of the sheath.
However, the split straw can easily disconnect from the fiber during manipulation, such as during insertion of the sheath into the patient. For example, the handle portion can easily catch on other objects, removing the split sheath, or by pushing the fiber and sheath together, the angle of the split straw can cause the split straw to pop off of the fiber. If the split straw comes off prematurely, the split straw may become unusable by touching a non-sterile surface. Additionally, having the small split straw become disengaged from the fiber would cause problems for the practitioner in positioning the fiber correctly and completing the procedure.
Thus what is needed is a device that aids the practitioner by providing a fiber positioning system that is easy to use in low-light conditions and that can be employed without requiring the used of a removable piece that is easily lost or tends to premature deployment.